Return flow carburetor



Dec. 15, 1964 T. M. BALL RETURN FLOW CARBURETOR Filed July 28, 1959 3 Sheets-Sheet l r LA INVENTOR. Ta-277.46'

Dec. 15, 1964 T. M. BALL RETURN FLOW CARBURETOR 3 Shee'f.s-Shee*.l 2

Filed July 28, 1959 f5! y 54 JNVENToR.

E!! 745677145 Mdzz Dec 15, 1964 T. M. BALL 3,161,700

RETURN FLow cARBuREToR Filed July 2s, 1959 a sheets-sheet s /i ya H .JY

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United States Patent Olicc 3,161,700 latented Dec. 15, 1954 This invention relates to improvements in a carburetor particularly adapted for use with an automobile internal combustion engine. This application is a continuationin-part of co-pendng application Serial No. 861,529, tiled May 28, 1959, now Patent No. 3,078,077.

In conventional carburetors, a iioat controlled fuel inlet needle valve is employed to regulate the fuel level inthe carburator fuel bowl. Small dirt particles sometimes interfer with effective operation of the valve, as for example by becoming lodged between mating valve seats which otherwise cooperate to regulate the fuel ilow into the fuel bowl. Also the oats require considerable size in order to be eective because of the comparatively low speciiic gravity of thefuel. In consequence the size of the fuel bowl must be appreciably larger than is otherwise desired. f

An important object of the present invention is to provide an improved carburetor which avoids the foregoing objections and in particular to provide a oatless carburetor lwhich does not require a fuel inlet needle valve. Y

Another object is to provide such a construction including an overtlow staudpipe in the fuel bowl having an upper opening which determines the maximum fuel level in the bowl. A fuel inlet pumpis provided to pump Y fuel into the bowl at a rate in excess of demand. The

excess fuel overflows into the standpipe and is' returned to the fuel tank.` In order to overcome adverse grade conditions .which-prevent the excess fuel from return-"` ing tothe tank by gravity ow, a scavenging pump is provided in the fuel `return line between the overflow Among other advantages of the above structure, elimination of the necessarily large float enables utilization of a comparatively small fuel bowl closely adiacent the inlet air induction conduits of a multiple barrel carburetor, for example. The smallfuel bowl thus located is less sensitive to grade land inertial eects and enables uniform fuel distribution to'eah of the several induction conduits. Also redculation of the fuel drives 0E its more volatile fuel fractions and thereby some of the problems` of the conventional lloat controlled carburetor, as for example thoseconcerned with vapor formation. f Y I In order to provide adequate fugl during maximum engine speed at wide open throttleg'a fuel inlet pump is 'provided which deliveries an excess supply of fuel to the fuel bowl during all operating conditions of the engine. When the throttle is suddenly closed while the engine is still operating at high speed, unless some provision is made to the contrary, va maior portion of the fuel supplied to the fuel bowl will be rdirculated. In general the life of a fuel pump and inparticular the life of an engine driven diaphragm ty'pe'pump, which is preferred for supplying fuelin the quantity required and at a substantially uniform pressure regardless of changes in engine speed, depends upon the quantity of fuel pumped.

For the above reasons, as well as the desirability of conserving power in an automobile engine and of minimizing fuel heating by excessive recirculation, another object of the present invention is to provide improved simple and highly eectve means for supplying fuel to the fuel bowl in reasonable and safe amounts related to engine requirements.

specification wherein like. reference characters pumping chamber. During movement of the diaphragm.

in the opposite direction in a pumping stroke, fuelis discharged from the pumping chamber into the fuel bowl. The diaphragm is secured to a plunger arm foi actuation thereby. A pumping spring under compression Vbetween the diaphragm and a fixed portion of the pump mechanism yielding urges the diaphragm in said opposite direction to cause the pumping stroke. A pivotal arm engageable with a rotating cam driven by the automobile engine to be pivotally oscillated thereby is also engageable with the plunger tomove the latter insaid one direction Y against the force of the pumping spring to compress the latter. The pivotal arm is'also .freely engageable with the plunger so that during the reverse pivotal movement of the arm, the latter will move independently of the plunger and release the diaphragm for spring urged pumping movement in said oppositegdirection, but will not positively urge movement ofthe diaphragm-in said opposite direction. ,In the pumping force will result entirely-from thewcomprcssed pumping spring and will be substantially constant regardless of the speed of the engine or of the pivotally-oscillated arma-1 i Other and more specific Aobjectsare tio-provide such a diaphragm pump and carburetorA combination having l i means for varying'the pumpingsiroke of In said opposite directiombyafdirectvt-linkage with-.the a throttle actuating mechanism, or-.by :pressurefactuated -means connected with the inlet sys,

tem or with the discharge sideof the scavenging pump.'

- other objects of :his invention-william. inthe fol. l' lowing description and appended claims, reerencebeing had to the accompanying drawings forminga partof this corresponding .parts in the several views-gv` FIGURE 1 is a schematic .new or a' son# less return iiow carburetor and pump embodying the present invention showing v means actuated by induction conduit pressure downstream of the throttle valve jfor controlling the diaphragm pumpingstroke.

1 illustrating a modilicat'ion..

FIGURE 3v is a view-smilar'to FIG FIGURE s is a view emunio 1, bnshew ing means actuated, by the scavengingfpumpdischarge pressure for controlling the diaphragm stroke. i

FIGURE 6 is a samt-mary view similar to FIGURE 5 illustrating a modification.

FIGURE 7 is a view similar to FIGURE 1 but showing a'mechanical linkage with the throttle mechanism for controlling the diaphragm stroke.

FIGURE 8 is a view-similar to FIGURE 7 illustrating a modtication.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also designate FIGURE 2 is a ngmnaryview ,to FIGURE'y A o p p QI,un sinktv Ing means actuated by Induction conduitvpressure at the portion of the casting is formed to provide an air horn 14 adapted to be connected with the usual air filter and opening at its downstream end into the venturi 11 to supply air thereto. The casting portions 10 and 14 are suitably secured together, as for example by screws not shown, and comprise an upper portion of the air inlet and fuel mixing induction system which extends downstream of the throttle valve 12 and discharges into the usual engine cylinders in a conventional manner.

Integral with the casting 10 in the present instance is a fuel bowl casting 15 containing an annular chamber or 20 fuel bowl 16 enclosing a cylindrical standpipe or wier 17 which also serves as an acceleration pump cylinder containing a plunger 18 reciprocable in its lower portion and secured to a plunger shaft 19 for actuation thereby.

Where desired the shaft 19 is connected by suitable link- 25 age with a pedal operated accelerator mechanism which controls the opening and closing of valve 12 to operate conjointly therewith. Upon upward movement of plunger 18, fuel is drawn into the lower portion of chamber 17 via condut'20- in communication with the bowl 16, 30

suitable check valve illustrated schematically as a ball check element 21 normally seats at the mouth of the duct 2 0 opening into the lower portion of 17 to prevent lo of fuel therefrom but is raiseddm its seat by the fuelllow into chamber 17 on the upstroke of plunger 35 18. Upon downward movement of plungerl the fuel is forced from chamber 17 into the induction conduit via acceleration fuel conduit 22, ball check valve 2 3, and nomle 24 which latter discharges into the induction con# duit at a location ixmnediately abovetbe throai'of venturi 40 11. The check valve 2 3 is schematically as a ball normally urged by a spring to a seated positibnclosing nozzle 24 from the interior of chamber 1'4,` tlieball being readily movable upward against the tension of ifs seating spring by the acceleration fuel pressure 'upon 45 downward movement of plunger 18. The main'fuei to' the engine via duct 25 at its lower end through metering port 26 into the fuel bowl 16 and communicates at its upper end with a fuel nozzle4 In accordance *with the structure described Lthus far,' fuel entering the body 16 in excess of engine requirements overliows the upper edge of standpipe 17 which 21 havingixs daehargeorm locaawithia the throat 50 thereby the fuel in the bowl 1.6, af a predctcb- 55 mined maximum level dcterinincdby the eicctive height of the standpipe 17 withoutrecinse toa, oat operated mechanism. Fuel is 'supplied to the bowl I6 from a suitable fuel taank via conduit 28.

-A multiple piece fuel pump housing comprising 60 an upper dome'38 and a lower basnl 39 cooperate with diaphragms 49 and 41 respectively to provide an' inlet fuel pumping or working chamber 42 and an exhaust fuel pumping or scavenging chamber 43. Springs 44 and 45 under compression between portions of housing 37 and A65 diaphragms 40 and 41 respectively urge the former diaf phragm upwardly and the latter diaphragm downwardly to effect the pumping strokes for the respective chambers 42 and 43.

The upper working chamber 42 comprises a portion 70 of supply duct 28 which communicates upstream of charnber 42 with the fuel tank. Fuel enters and leaves chamber 42 via an inlet port 45 and a discharge port 47 associated with check valves 43 and 49 respectively. Upon downward movement of diaphragm 40 as explained be- 75 low, fuel is drawn in the direction of the arrow 28a from the tank and through inlet port 46 into working chamber 42. During this operation ball valve 48 is forced from its seat at port 46 by the fuel flow, and ball valve 49 seats at the discharge port 47 to close the latter from the fuel bowl 16. Upon upward movement of diaphragm 40, ball valve 48 is caused to seat at port 46 to close theworking chamber 42 from the fuel tank. During this operation, the pressure exerted in chamber 42 unseats ball valve 49 from port 47 and supplies fuel via conduit 28 to the fuel bowl 16. The spaces at the sides of the diaphragms 40 and 41 opposite chambers 42 and 43 respectively are vented to the atmosphere by ducts 50 and 51 to facilitate the pump operation. i;

Fuel is returned in the direction of arrow 52dI from standpipe 17 to the fuel tank via fuel return conduit 52 which includes chamber 43 as a portion thereof. Upstream, the conduit 52 communicates with standpipe 17 at a locationabove the uppermost limit of movement of plunger 18. The retum fuel enters chamber 43 via port S3 and discharges from chamber 43 via port 54. Ball check valves and 56 are associated with ports 53 and 54 respectively, so that upon upward movement of diaphragm-41 as described below, ball 56 seats against port 54 to close chamber 43 from the fuel tank. During this nnmication chamber 43 and standpipe 17 and to draw fuel hom the latten Upon downward movement of diaphragm 41, ball 55 is seated against port 53 to close. chamber 43 from standpipe 17. Simultaneously-f ball 56 is unseated from port 54 bythe pressure in cham# .ber 43 to discharge fuel from the latter in the direction of arrow 52a to the tank. Movement limiting pins in the conduits 28 and 52 associated with the ball valves 48, 49,

ss and 5s prev-saumur: movement offhe'bansfrom their i associated ports. Inasmnclt as the check valves are' wellknown, tbeseare merely shown schematically and are not discussedV u.-flil'thiei?dctaljlf .Aauationofthediapbragms 49 and41 is accomplished by drvingshafts 57 and Sfconnected toth'ese andA t in enlarged heads59 and 60 respectively.- Pivotal levers 61 and, 62 are pivodvon housing 37- at locations 63. and 64 respectively between their ends. Each lever has one end e'with arotating eccentric cam 65 mounted onA a shaft 66 dxiven by the automobile engine. The opposite ends of the levers 61 and 62 are provided oversized-'openings 61 and 68 through which the rods 57 and 58' extend freely toA enable their relative sliding movement with respect to the levers 61 and `6 2 uutilrthe levers engage the enlarged heads, 59

Upon of the automobile engine, shaft 66= is rotated to tum' cam 65 and' thereby cause pivoting ofl levers 61 and 62. Upon clockwise pivoting'of lever 61;V or counterclockwse pivoting of level- 62,'.the head 59 or isengagedt'op'ull rod 57 or 58 inthe direction fo compress the spring or 4S as the case might be; Upon counterclockwise pivoting of lever 61 and clockwise pivoting of lever 62, thev oversized openings 67 and 68 enable the levers to swing independently of the shafts 57 and S8, whereupon and 45 are released to force diaphragms 40 and 41 in pumping actions tow-ard the associated dome 38 and basin 39; -The pivotal action of levers 61 and 62 merely compresses the springs 44 and 45A alternately, which latter thencxert resilient force to effect the pumping action of the asso ciated diaphragms 40 and 41. In consequence, fuel is discharged from chamber 42 at a uniform optimum pressure determined by the force of spring 44. Upon the upward spring urged pumping stroke of diaphragm 40, fuel is dis` charged via port 47 to fuel bowl 16. All fuel in excess. of engine requirements overflows the standpipe 17 and returns by conduit S2 to chamber 43 via port 53, whereupon the fuel is pumped to the fuel tank by downward spring urged pumping movement of diaphragm 41.

WWA. a 4

In order to prevent too great an excess of fuel from being pumped to fuel bowl 16 when the engine is operating at comparatively light load, means are provided for limiting the maximum movement of diaphragm 40 during the spring urged pumping stroke. As illustrated in FIG- URE l, eccentric cam 69 is keyed to a pivot shaft 70 mounted within housing 37 and extending to the exterior thereof. Keyed to shaft 70 to pivot therewith and with cam 69 is a swinging lever 71 which extends upward at a location exteriorly of housing 37 and is pivotally secured at its upper end at 72 to the outer end of a plunger shaft 73. Cam 69 directly overlies the central portion of diaphragm 40 and is shaped so that upon being pivoted counter-clockwise in FIGURE 1,'diaphragm 40 will be depressed. Plunger 73 extends freely through an air vent and guide opening 74 in the wall of a pressure chamber 75. The latter is partitioned by a diaphragm 76 which is normally urged to the right in FIGURE l by coil spring 77 disposed between housing 75 and diaphragm 76.

Variations in engine fuel requirements are detected by conduit 78 which connects pressure chamber 75 at the left of diaphragm 76 with the low pressure region of induction conduit downstream of throttle valve 12. When the engine is operating at light load and throttle valve 12 is partially closed, the low pressure applied through conduit 78 to the-left side of diaphragm 76 will cause the latter to be forced to the left against the pressure of spring 77, thereby swinging lever 71 and cam 69 counterclockwise about the axis of shaft 70 to reduce the pumping stroke of diaphragm 40.

In the converse action, as throttle valve 12 progressively moves toward an open position, the pressure conveyed to the left side of diaphragm 76 by conduit 78 increases,

enabling rightward movement of diaphragm V76 in accordance with the vforce of spring '77. In consequence, lever 71 and cam 69 are pivoted clockwise about the Yaxis of f shaft 70 to enable an increased pumping stroke of -diaphragm 40. Thus with decreasedengine load, Vthe pumping stroke of vdiaphragm is decreased, the fuel ow pumped via conduit Z8 into fuel bowl 16 is decreased, and recirculation of fuel to the bowl 16 is minimized. With increasing engine load, the increased pumping strokefenabled by diaphragm 40 increases the fuel ow via. conduit 28tofuelbowl16. p'

Referring to FIGURE 2, another means for varying the etective stroke of the pumping diaphragm 40 is illusuated wherein cam '69, shaft :70 and lever 71 are o mitted entirely. A wedge-shaped cam 79 is secured to the outer end of plunger 73 and is arranged to be inserted between pivotal lever 61 and cam 65 in accordance with movement of diaphragm .76. In other respects the structure and operation ofthe mechanism of YFIGURE 2 is the same as in FIGURE l, so that only a fragmentary portion is illustrated in FIGURE 2 and identical parts are numbered the same inbothdrawings. i .11 J In FIGURE 2 the spring urging upward movement oi diaphragm 40 aud corresponding to spring 44 will be under substantially no comprpssion when the pivotal lever .61 is in the horizontal position shown. Accordingly the diaphragm 40 will be at the upper limit of its pumping stroke, as in FIGURE 1. Itis apparent that upon right- -Ward movement of wedge 79 between the left end of lever `61 and cam 65, the lost .motion between arm 61 and enlargement 59 will be d and the downward spring compressing stroke of gdiaphragm 40 will be'increased, thereby to increase the etectivc upward fuel pumping stroke of diaphragm 40. Thus th progressively increasing engine load and decreasirgkipressure of conduit '78, spring 77 will gradually urge plunger 73 and wedge 79 to the right between lever 61 and cam 65 so as to increase the effective pumping stroke and the fuel supply to the engine. It is also apparent that during low load operation of the engine, when throttle valve 12 moves to its closed position and the pressure in conduit 78 is a minimum, diaphragm 76 will be moved leftward to the position shown in FIGURE 2 so as to withdraw wedge 79 from engagement between cam 65 and lever 61, thereby to minimize the fuel pumping stroke of diaphragm 40 and also to minimize the fuel pumped to bowl 16.

Although the structure of FIGURES l and 2 provide means for supplying fuel to bowl 16 at a rate which is a function of engine load, the vacuum induced force below valve 12 is at its maximum at low engine load and progressively decreases as engine load increases. Accordingly at comparatively high engine load when the throttle valve 12 is open fully or nearly so, the vacuum force acting on diaphragm 76 is a minimum. Thus changes in the throttle position result in comparatively low magnitude pressure changes on diaphragm 76.

Where increased effectiveness of the vacuum induced force at high engine load is desired, constructiopg such as illustrated in FIGURES 3 and 4 are preferred. The general arrangement of the return ilow carburetor and pump is the same in FIGURES 3 and 4 as in FIGURES l and 2 so that identical parts are numbered the same in all views. The distinctions in FIGURE 3 over FIGURE 1 are that conduit 78 connects chamber 75 at the left of diaphragm 76 with the induction conduit adiacent the throat of venturi 11 and cam 69 is adjusted on shaft 70 so as to depress diaphragm 40 and limit its pumping stroke upon clockwise pivoting of lever 71 and cam 69. Upon counterclockwise pivoting of lever 71 and cam 69, the pumping stroke of diaphragm 40 urged by spring 49 is increased.

Accordingly as engine load increases, the vacuum induced force at the throat of venturill increases and becomes a maximum at wide open throttle. The resulting low pressure at the left of diaphragm 76 results in leftward movement of diaphragm 762'aud plunger 73 aginst the force of spring 77 to `pivot'lever 71 and cam 69 counterclockwise and increase the fuel pumping stroke ofdiaphragm 40. In consequence, as the airllow through venturi throat 11 increases with increasing engine load, the fuel liow into bowl 16 increases; VConversely as airiiow through venturi throat 11 decreases with decreasing engine load, the vacuum induoed'force at the left of diaphragm 76 decreases, enabling spring77 to pivot plunger 73 and lever 71 clockwise and decrease the pumping stroke of diaphragm 40, thereby to decrease the fuel flow intobowll. M

In the FIGURE 3 construction, vthe vacuum induced force at the throat of venturir 11 becomes a minimum at low engine load. Accordingly where desired Ya dual control of the inlet fuel liow asillustrated in both FIG- URES l and 3 may be employed to assure adequate opl erating force during conditions of both high and low engine loads. l 1

FIGURE 4. shows .a structure .much like FIGURE 2 wherein lever-:71, shaft 70 and cam"69 are eliminated, and wherein carburetor and fuel pumpare thersame. as in FIGURE 3.: In FIGURE 4, plunger 73 extends slidably and in fluid sealing engagement at 74a through the side wall of pressure chamber 75a.:and is provided with a wedge-shaped cam 79 as in FIGURE 2. Also in FIG- UREl 4, spring 77 is located at the right side of diaphragm 76 to urge the latter leftward; Diaphragm 76 partitions chamber 75a into two' partsas-in the earlier views, but in this instance,l the left part of the chamber is vented to the atmosphere at 80. Conduit 78 is connected with chamber 75a at the right side of diaphragm 76 and is also connected with the induction conduit adjacent the throat of venturi 11 as in FIGURE 3.

With increased engine load and decreased pressure in conduit 78, diaphragm 76 is urged against the force of spring 77 to the right so as to insert wedge 70 between lever 61 and cam 65 and thereby increase the etective pumping stroke of diaphragm 40 as explained above in regard to FIGURE 2. Also as in FIGURE 2, the spring urging diaphragm 40 upward in FIGURE 4 is in its uncompressed conditon when lever 61 is in the horizontal y 52 downstream of pumpii position shown. Accordingly diaphragm 40 is at the upper limit of its pumping stroke in FIGURE 4. At low engine load and air ow through venturi 11, the increased pressure in conduit 78 enables spring 77 to urge diaphragm 76 and plunger 73 leftward, thereby to withdraw Wedge 70 from between lever 61 and cam 65 to the position illustrated in FIGURE 4 whereas the pumping stroke is a Accordingly as in the FIGURE 2 construction, the pumping stroke of diaphragm 49 and the fuel supply to fuel bowl 16 is increased with increasing load. Conversely with decreasing load, the pumping stroke and the fuel supply to bowl 16 are decreased.

FIGURE 5 also illustrates a return ow carburetor and pump as described above wherein corresponding parts are numbered the same. In FIGURE 5, cam 69, shaft 70 and arm 71 are arranged as in FIGURE 1 to reduce the pumping stroke of diaphragm 40 upon counterclockwise pivoting of cam 69, and to increase the pumping stroke of diaphragm 40 upon clockwise pivoting f cam 69. In FIGURE 5, instead of employing the induction conduit pressure to control the movement of diaphragm 76 in accordance with engine load, a conduit 81 connects the upper right side of chamber 75 with the return ow conduit 52 -at a location downstream of pumping chamber 43, thereby to regulate the pressure at the right of diaphragm 76 as a function of the return fuel ow. In order to accentuate the pressure changes in conduit 81, a restriction S2 is provided in conduit 52 at a location downstream of the latters connection with conduit 81.

In accordance withthe structure of FIGURE 5, when engine load and fuel consumption drop, the return flow through conduit 52 normally tends to increase. The iucreased return fuel ow is indicated by an increased presf sure in the portion of conduit 52 between pumping chamber 43 and restriction 82. This pressure increase is transmitted by conduit 81 to latter leftward against the force -of spring 77 and cause counterclockwise pivoting progressively decrease the pumping stroke of diaphragm 40. Thus the fuel ow to bowl 16 is reduced and circulation of fuel through the bowl 16 is decreased until the latter fuel ow attains an equilibrium condition de-n termined by the new engine load requirement.

It is'also apparent that upon an increase in fuel con sumption by 'the engine, the fuel return llow in conduit 52 will decrease and the pressure :in conduit 81 acting on the right side of diaphragm 76 will likewise decrease, enabling spring 77 to urge diaphragm 76 rghtward to pivot lever 71 and cam' 69 clockwise. The pumping stroke of diaphragm 4,0 and the fuel ow to bowl 16 diaphragm 76 to urge the t of lever 71 and cam 69 to' thus increase` until the 'system again reaches the desired i equilibrium condition determined by the ifuel requirements at the new engine load. The foregoing structure is independent of pressure changes in theinduction conduit and depends only upon the rate of return fuel ow in conduit S2, which isethus regulated to a desired nominal value during all conditions of engine operation.

FIGURE 6 illustrates a fragmentary portion of the carburetor and diaphragm pump cam 69, shaft 70, and lever 71 are omitted. In FIGURE 6 conduit 81 is connected with chamber 75a at the right of diaphragm 76 and also. with the return flow conduit 5. Chamber 75a is to the corresponding chamber of FIGURE 4, except that spring 77 in the left part of chamber 75a urges diaphragm 7 to the right. Port 80 vents the left side of chamber 75- atmosphere. 'Ihe plunger 73 extends rghtwardly at 74a through the side wall of chamber 75a in fluid sealing engagement and is provided with a wedge-shaped cam 79 which is insertable between lever 61 and cam 65 upon rightward movement of plunger 73, as in FIGURES 2 and 4. In other respects, the structure and operation of the pump and carburetor mechanism arev4 the same as in the abovede of FIGURE 5 wherein chamber 43 as in FIGURE scribed views, so that corresponding parts are numbered the same.

During low engine loads when fuel consumption is low and the return dow fuel from chamber 43 is comparatively high, pressure in line 81 is 'high as described above and urges diaphragm 76 leftward against the force of spring 77 to withdraw wedge 79 from between lever 61 and cam 65. In this condition, the spring urging upward movement of diaphragm 40 in FIGURE 6 is not stressed when the lever 61 is in the horizontal position shown. Accordingly diaphragm 40 is at the upper limit of its pumping stroke and the pumping stroke will be a minimum during rotation of cam 65. As fuel consumption increases with increasing engine load, the return flow in line 52 drops and correspondingly the pressure in conduit 81 drops, enabling spring 77 to urge plunger 73 and wedge 79 to the right between lever 61 and cam In consequence, the lost motion between lever 61 ah enlargement 59 illustrated in FIGURE 5 is decreased and the effective pumping stroke of diaphragm 40 is increased so as to supply an increased quantity of fuel to the fuel bowl 16 with increasing engine load. v

FIGURE 7 illustrates the return flow carburetor and pumping mechanism as in FIGURE 1 wherein corresponding parts are again numbered the same. In FIG- URE 7 however, instead of controlling the pumping stroke of diaphragm 40 by induction conduit pressure as in FIGURES 1 4, or by return ow fuel pressure as in FIGURES 5 and 6, the pumping stroke is controlled by a mechanical linkage with the accelerator mechanism.

In FIGURE 7, pressure chamber 75 and vertical levery 71 are eliminated. A generally horizontal lever Y83 is keyed at one end to alateral external extension of cam shaft 70 which in turn diaphragm 40 as in FIGURE 1. Cam 69 is disposed to enable increased upward ragm 40 when lever 83 is swung clockwise about the axis of shaft 70. The left end of shaft 83 is provided with a transverse pin 84 slidably secured within the yoke 85 of a pivotal shaft 86 pivotally mounted between .its endsat87toaxedporton ofthe carburetorcasting-15.

The left end of shaft 86 is pivotally connected at 88 to.

the upper end of a connecting link 89. The lower end of link 89s"pivotally connected at 90 to the outer swingingendofncrankarm91whichinturniskeyedtoan extension of valve shaft 13 exteriorly of the induction conduit 10.'v i

Upon pivoting linkage 92 which is suitably connected with crank arm 91 and the customary pedal operated throttle valve 12 is opened or closed. When crank arm 91 is pivoted clockwise, throttle valve 12 is progressively opened and link 89 is moved about the axis of shaft 70and raise the' -point of movement limiting engagement between diaphragm 40 and cam 69. In consequence, upon opening of'throttle valve 12 during increased engine load, the'pumping stroke of diagram 40 and the fuel flow to fuel bowl 16 are increased.

Upon counterclockwise or' closing movement of valve 12 with decreasing engine load, lever 89 is moved upwardly, lever 86 is pivoted clockwise about the axis of pivot 87, and link 83 and cam 69 are pivoted counterclockwise to the position shown in FIGURE 7 to the pumping stroke of diaphragm 40 and the fuel supply to` ,bowl 16.

' FIGURE 8 is concerned with a carburetor, pumping mechanism, and throttle actuated linkage including crank arm 91, links 86 a1ld89, and yoke 85, as in FIGURE 7, but wherein lever 83 and cam'69 are eliminated. A pin 93 slidable Within yoke 85 in the manner of pin 84 of FIGURE 7 is secured to one end of a dog leg link 94 pivoted at 95 to a fixed bracket portion 37a of housing 37. The other end of dog leg link 94 comprises a vertical yoke 96 having a pin 97 slidably retained therein.

is keyed to cam 69 overlying pumping movement of dlaphof crank arm 91, {asfor example by' i downward to swing lever 86 counterclockwise, thereby to pivot lever 83 clockwise' v Pin 97 extends transversely through a generally horizontal extending shaft 9S having tapered wedge cam 79 at its left end arranged to be inserted between lever 61 and cam 65 as in FIGURES 2, 4, and 6. Shaft 98 is also slidably supported within bracket portion of housing 37a for horizontal movement.

Upon clockwise pivoting of crank arm 91 to open throttle valve 12, lever 86 is pivoted counterclockwise as aforesaid, causing dog leg link 94 to pivot clockwise and move wedge 79 between lever 61 and cam 65 to take up the lost motion between lever 61 and enlargement 59 and thereby to increase the elective pumping stroke of diaphragm 40 as described above in regard to FIGURES 2, 4, and 6. In this regard, the spring which urges upward pumping movement of diaphragm 40 will be determined so as to be in an unstressed condition when lever arm 61 is in the horizontal position illustrated. Thus diaphragm 40 will be at the upper limit of its pumping movement when wedge 79 is at the Withdrawn position illustrated in FIGURE 8. As Wedge 79 is moved rightward in FIGURE 8 upon opening of throttle 12 with increasing engine load, the effective pumping stroke of diaphragm 40 and the fuel supplied to bowl 16 is increased. Conversely as wedgeV 79 is withdrawn leftward upon closure of throttle 12 with decreasing load, the effective pumping stroke of diaphragm 40 and the fuel dow to bowl 16 is decreased.

Having thus described my invention, I claim:

l. In a carburetor for an internal combustion engine, movable wall-type pumping means for connecting a source of fuel with said carburetor, fuel flow control means for controlling the fuel flow to said carburetor, said pumping means having a reciprocable wall movable in alternate intake and pumping strokes, resilient means for yieldingly urging said wall in said pumping strokes, a pivotal actuating lever, means operatively connecting said lever and wall for alternately moving the same in said intake strokes in opposition to said resilient means and for releasing said wall for movement in said pumping strokes upon alternate pivoting of said lever in opposite directions, operable cam means for pivoting said lever in said opposite directions including a cyclical cam and adjustment means for varying the amplitude of said pumping strokes, said adjustment means operatively connecting said cam and lever to adjust the angular relationship of said lever with respect to said cam, and means responsive to operation of said fuel ow control means for actuating said adjustment means to increase the amplitude of said pumping strokes upon operation of said fuel ow control means to increase said fuel flow.

2. In a carburetor for an internal combustion engine, movable wall-typenumping means for connecting a source of fuel witl said carburetor, said pumping means having a reciprocable wall movable in alternate intake and pumping strokes, resilient means for yieldingly urging said wall in said pumping strokes, a pivotal actuating lever, means operatively connecting said lever and wall for alternately moving theh same in said intake strokes in opposition to said resilient merans and for releasing said wall for movement in said pumping strokes upon alternate pivoting of said lever in opposite directions, the last named connecting means providing adjustable lost motion between said lever and wall for determining the extent of the latters pumping stroke, operable cam means for pivoting said lever iri said tkopposite directions including a cyclical cam and adjustment means for varying the amplitude of said pumping strokes; said adjustment means operatively connecting said cam lever to adjust said lost motion, and means responsive to operation of said fuel iiow control means for actuating said adjustment means to increase the amplitude of said pumping strokes upon operation of said fuel ow control means to increase said fuel flow.

3. In a carburetor for an internal combustion engine having an air intake manifold system, ow control means for controlling the air flow in said system, movable wall type pumping means for connecting a source of fuel with said carburetor, said pumping means having a reciprocable wall movable in alternate intake and pumping strokes, resilient means for yieldingly urging said wall in said pumping strokes, a reciprocating member, means operatively connecting said member and wall for alternately moving the same in said intake strokes in opposition to said resilient means and for releasing 'said wall for movement in said pumping strokes upon alternate reciprocating of said member in opposite directions, adjustable movement limiting means engageable with said pumping means to limit the length of the pumping stroke thereof, and means responsive to operation of said ow control means and operatively connected with said movement limiting means to adjust the latter to increase said pumping stroke with increasing air tlow insaid system.

4. ln a carburetor for an internal combustion engine having au air intake manifold system, liow control means for controlling the air ilow in said system, movable wall type pumping means for connecting a source of fuel with said carburetor, said pumping means having a reciprocable wall movable in alternate intake and pumping strokes, resilient means for yieldingly urging said wall in said pumping strokes, a reciprocating member, means operatively connecting said member and wall for alternately moving the same in said intake strokes in opposition to said resilient means and for releasing said wall for movement in said pumping strokes upon alternate reciprocating of said member in opposite directions, operable cam means for reciprocating said member in said opposite directions including a cyclical cam and adjustment means for varying said pumping strokes, said adjustment means operatively connecting said cam and member to adjust the relative position of said member with respect to said cam,

and means responsive to operation of said flow control means for actuating said adjustment means to increase said pumping stroke with increasing air ilow in said system.

5. In combination, a carburetor for an internal comb uston engine having an air intake manifold, a fuel bowl, duct means connecting said fuel bowl with said manifold for supplying fuel thereto, fuel ow control means for controlling the fuel tlow from said bowl to said manifold, movable-wall type fuel pumping means connected with said bowl for supplying fuel thereto, means for maintaining the fuel in said bowl at a predetermined level comprising an overliow weir delining a sidewall portion of said bowl arranged for liow of excess fuel thereover when the fuel in said bowl attains said predetermined level, said pumping means having a reciprocable wall movable in alternate intake and pumping strokes, adjustable movement limiting means engageable with said pumping means to limit the length of said pumping strokes, and amplitude control means responsive to operation of said fuel iiow control means and operatively connected with said limiting means to adjust the latter to increase the amplitude of said pumping strokes with increasing fuel ow from said bowl to said manifold, said pumping means including oscillating means operatively engageable with saidfwall for moving the same in said alternate intake and pumping strokes, cyclic cam means, said movement limiting means operatively connecting said cam and oscillating means for operating the latter to move said wall in said alternate intake and pumping strokes and being adjustable to increase the amplitude of said pumping strokes upon operation of said fuel-dow control means to increase said fuel flow.

6. In combination, a carburetor for an internal combustion engine having an air intake manifold, a fuel bowl, duct means connecting said fuel bowl with said manifold for supplying fuel thereto, fuel tiow control means for controlling the fuel ow from said bowl to said manifold, movable-wall type fuel pumping means connected with said bowl for supplying fuel thereto, means for maintaining the fuel in said bowl at a predetermined level comprising an overflow weir defining a sidewall portion of said bowl arranged for ow of excess fuel thereover when the fuel in said bowl attains said predetermined level, said pumping means having a reciprocable Wall movable in alternate intake and pumping strokes, adjustable movement limiting means engageable with said pumping means to limit the length of said pumping strokes, and amplitude control means responsive to operation of said fuel .iiow control means and operatively connected with said limiting means to adjust the latter to increase the amplitude of said pumping strokes with increasing fuel ow from said bowl to said manifold, said intake manifold having a venturi throat therein, said duct means being connected with said intake manifold adjacent said throat for increasing the fuel supplied thereto with increasing air ow therein, said fuel control means including a throttle valve in said manifold downstream of said throat for controlling said air o'w, said pumping means including oscil lating means operatively engageable with said Wall for moving the same in said alternate intake and pumping strokes, cyclic cam means, said movement limiting means operatively connecting said cam and oscillating means for operating the latter to move said wall in said alternate intake and pumping strokes and being adjustable to vary the amplitude of said pumping means, and said amplitude control means being in communication with said manifold and being responsive to the air low therein and being also operatively connected with said movement limiting means to adjust the latter to increase the length of said pumping strokes with increasing air ow in said manifold.

References Cited in the tile of this patent UNITED STATES PATENTS 1,722,735 Deland July 30, 1929 1,881,860 Muzzy Oct. 11 1932 2,050,567 Griin et a1. Augxl'l, 1936 2,136,959 Winfield Nov. 15, 1938 2,254,850 Mallory Sept. 2, 1941 2,469,965 Udale Oct. 22, 1946 2,734,729 Loftin Feb. 14, 1956 2,905,455 Eberhardt Sept. 22, 1959 FOREIGN PATENTS 931,268 France Feb. 18, 1948 

1. IN A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE, MOVABLE WALL-TYPE PUMPING MEANS FOR CONNECTING A SOURCE OF FUEL WITH SAID CARBURETOR, FUEL FLOW CONTROL MEANS FOR CONTROLLING THE FUEL FLOW TO SAID CARBURETOR, SAID PUMPING MEANS HAVING A RECIPROCABLE WALL MOVABLE IN ALTERNATE INTAKE AND PUMPING STROKES, RESILIENT MEANS FOR YEILDINGLY URGING SAID WALL IN SAID PUMPING STROKES, A PIVOTAL ACTUATING LEVER, MEANS OPEATIVELY CONNECTING SAID LEVER AND WALL FOR ALTERNATELY MOVING THE SAME IN SAID INTAKE STOKES IN OPPOSITION TO SAID RESILIENT MEANS AND FOR RELEASING SAID WALL FOR MOVEMENT IN SAID PUMPING STROKES UPON ALTERNATE PIVOTING OF SAID LEVER IN OPPOSITE DIRECTIONS, OPERABLE CAM MEANS FOR PIVOTING SAID LEVER IN SAID OPPOSITE DIRECTIONS INCLUIDNG A CYLICAL CAM AND ADJUSTMENT MEANS FOR VARYING THE AMPLITUDE OF SAID PUMPING STROKES, SAID ADJUSTMENT MEANS OPERATIVELY CONNECTING SAID CAM AND LEVER TO ADJUST THE ANGULAR RELATIONSHIP OF SAID LEVER WITH RESPECT TO SAID CAM, ADN MEANS RESPONSIVE TO OPERATION OF SAID FUEL FLOW CONTROL MEANS FOR ACTUATING SAID ADJUSTMENT MEANS TO INCREASE THE AMPLITUDE OF SAID PUMPING STROKES UPON OPERATION OF SAID FUEL FLOW CONTROL MEANS TO INCREASE SAID FUEL FLOW.
 3. IN A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE HAVING AN AIR INTAKE MANIFOLD SYSTEM, FLOW CONTROL MEANS FOR CONTROLLING THE AIR FLOW IN SAID SYSTEM, MOVABLE WALL TYPE PUMPING MEANS FOR CONNECTING A SOURCE OF FUEL WITH SAID CARBURETOR, SAID PUMPING MEANS HAVING A RECIPROCABLE WALL MOVABLE IN ALTERNATE INTAKE AND PUMPING STROKES, RESILIENT MEANS FOR YIELDINGLY URGING SAID WALL IN SAID PUMPING STROKES, A RECIPROCATING MEMBER, MEANS OPERATIVELY CONNECTING SAID MEMBER AND WALL FOR ALTERNATELY MOVING THE SAME IN SAID INTAKE STROKES IN OPPOSITION TO SAID RESILIENT MEANS AND FOR RELEASING SAID WALL FOR MOVEMENT IN SAID PUMPING STROKES UPON ALTERNATE RECIPROCATING OF SAID MEMBER IN OPPOSITE DIRECTIONS, ADJUSTABLE MOVEMENT LIMITING MEANS ENGAGEABLE WITH SAID PUMPING MEANS TO LIMIT THE LENGTH OF THE PUMPING STROKE THEREOF, AND MEANS RESPONSIVE TO OPERATION OF SAID FLOW CONTROL MEANS AND OPERATIVELY CONNECTED WITH SAID MOVEMEANT LIMITING MEANS TO ADJUST THE LATTER TO INCREASE SAID PUMPING STROKE WITH INCREASING AIR FLOW IN SAID SYSTEM. 